Inhaler

ABSTRACT

An inhaler comprising a housing to receive a strip having a plurality of blisters is disclosed. Each blister has a puncturable lid and contains a dose of medicament for inhalation by a user. A mouthpiece is pivotally mounted to the housing through which a dose of medicament is inhaled by a user. The inhaler also has an actuating mechanism including a lever operable to sequentially move each blister into alignment with a blister piercing member depending from the mouthpiece. The actuating lever is also operable to cause the mouthpiece to pivot so that the blister piercing member punctures the lid of an aligned blister so that, when a user inhales through the mouthpiece, an airflow through the blister is generated to entrain the dose contained therein and carry it, via the mouthpiece, into the user&#39;s airway.

FIELD OF THE INVENTION

This application claims priority to Great Britain Application No.1020130.9 filled Nov. 26, 2010 the disclosure of which is herebyincorporated by reference,

BACKGOUND

The present invention relates to an inhalation device for oral or nasaldelivery of medicament in powdered form. More specifically, theinvention relates to an inhaler having a housing to receive a striphaving a plurality of blisters spaced along the length of the strip,each blister having a puncturable lid and containing a dose ofmedicament for inhalation by a user. The invention also relates to aninhaler containing a strip of blisters each having a puncturable lid andcontaining a dose of medicament for inhalation by a user of the deviceaccording to the invention.

Oral or nasal delivery of a medicament using an inhalation device is aparticularly attractive method of drug administration as these devicesare relatively easy for a patient to use discreetly and in public. Aswell as delivering medicament to treat local diseases of the airway andother respiratory problems, they have more recently also been used todeliver drugs to the bloodstream via the lungs, thereby avoiding theneed for hypodermic injections.

It is common for dry powder formulations to be pre-packaged inindividual doses, usually in the form of capsules or blisters which eachcontain a single dose of the powder which has been accurately andconsistently measured. A blister is generally cold formed from a ductilefoil laminate or a plastics material and includes a puncturable lidwhich is permanently heat-sealed around the periphery of the blisterduring manufacture and after the dose has been introduced into theblister. A foil blister is preferred over capsules as each dose isprotected from the ingress of water and penetration of gases such asoxygen in addition to being shielded from light and UV radiation all ofwhich can have a detrimental effect on the delivery characteristics ofthe inhaler if a dose becomes exposed to them. Therefore, a blisteroffers excellent environmental protection to each individual drug dose.

Inhalation devices that receive a blister pack comprising a number ofblisters each of which contain a pre-metered and individually packageddose of the drug to be delivered are known. Actuation of the devicecauses a mechanism to breach or rupture a blister, such as by puncturingit or peeling the lid off, so that when the patient inhales, air isdrawn through the blister entraining the dose therein that is thencarried out of the blister through the device and via the patient'sairway down into the lungs. Pressurized air or gas or other propellantsmay also be used to carry the dose out of the blister. Alternatively,the mechanism that punctures or opens the blister may push or eject thedose out of the blister into a receptacle from which the dose maysubsequently be inhaled.

It is advantageous for the inhaler to be capable of holding a number ofdoses to enable it to be used repeatedly over a period of time withoutthe requirement to open and/or insert a blister into the device eachtime it is used. Therefore, many conventional devices include means forstoring a number of blisters each containing an individual dose ofmedicament. When a dose is to be inhaled, an indexing mechanism moves apreviously emptied blister away from the opening mechanism so that afresh one is moved into a position ready to be opened for inhalation ofits contents.

An inhaler of the type described above is known from the Applicant's ownco-pending international application that has been published asWO2005/037353 A1.

According to one embodiment described and claimed in WO 2005/037353 A1,and illustrated in FIGS. 1 and 2 of the accompanying drawings, aninhaler 1 has a housing 2 containing a coiled strip of blisters 3. Anindexing mechanism 4 comprising a single actuating lever 5 unwinds thecoil 3 one blister at a time so that they pass over a blister locatorchassis 6 and successively through a blister piercing station 7, whenthe actuator 5 is pivoted in a direction indicated by arrow “A” in FIG.2. The blister 3 a located at the blister piercing station 7 on eachmovement of the actuator 5 is pierced on the return stroke of theactuator 5 (in the direction indicated by arrow “B” in FIG. 2) bypiercing elements 8 on the actuator 5 itself so that, when a userinhales through a mouthpiece 9, an airflow is generated within theblister 3 a to entrain the dose contained therein and carry it out ofthe blister 3 a via the mouthpiece 9 and into the user's airway.

The device known from WO2005/037353 A1 has already been modified so asprovide a fully integrated device, i.e. one in which the used blistersare retained within its housing so that a user never has to come intodirect contact with the blister strip. In one modified embodiment, knownfrom the Applicant's own previous application that has now beenpublished as WO09/007,352 A1, there is provided a flexible and resilientspiral element mounted within the housing of the device into which theused portion of the blister strip is directed so that, as the strip isgradually used up, the spiral expands as more and more of the strip isfed or pushed into it between its coils. The inhaler of the presentinvention, in its preferred form, is also a fully integrated device thatretains the used blisters, although in a preferred embodiment it has awall to separate the interior of the housing into used and unusedblister compartments. The wall is preferably rigid and slideably mountedso that the size of the unused and used blister compartments changesrelative to each other as the number of blisters that are used increasesand the number of unused blisters decreases.

The aforementioned document also describes an embodiment in which usedblisters are crushed between the blister strip drive or indexing wheeland the inner surface of the casing of the device, which is also afeature of the inhaler of the present invention. As crushing takes placeas the used strip passes around the blister strip drive member, a curlor curved form is imparted to the strip which helps it to coil up withinthe chamber.

The inhaler of the invention may also incorporate a blister strip drivemechanism or indexing mechanism that forms the subject of theApplicant's own previous international application that has nowpublished as WO2009/092652 A1.

The disclosures of WO2005/037353 A1, WO09/007,352 A1 and WO2009/092652A1 are all incorporated herein by reference.

SUMMARY OF THE INVENTION

The present invention seeks to provide another inhalation device of thetype disclosed in the above-mentioned applications, and which also has arelatively simple construction, is robust, straightforward tomanufacture and easy for the patient to use.

According to the invention, there is provided an inhaler comprising ahousing to receive a strip having a plurality of blisters, each blisterhaving a puncturable lid and containing a dose of medicament forinhalation by a user, a mouthpiece mounted to the housing and throughwhich a dose of medicament is inhaled by a user, a blister piercingmember mounted for rotation about a first axis and an actuatingmechanism including an actuating lever mounted for rotation about asecond axis to sequentially move each blister into alignment with theblister piercing member, wherein the actuating lever cooperates with theblister piercing member so that the blister piercing member pivots aboutsaid first axis in response to rotation of the actuating member from aninitial position about the second axis to puncture the lid of an alignedblister so an airflow through the blister is generated to entrain thedose contained therein and carry it, via the mouthpiece, into the user'sairway when a user inhales through the mouthpiece.

In a preferred embodiment, the blister piercing member is fixed to themouthpiece and the mouthpiece is pivotally mounted to the housing sothat the mouthpiece pivots, together with the blister piercing member,about said first axis in response to rotation of the actuating leverabout the second axis.

In another embodiment, the blister piercing member is pivotally mountedto the mouthpiece for rotation about said first axis so that the blisterpiercing member pivots about said first axis relative to the mouthpiece,in response to operation of the actuating lever.

Preferably, the actuating lever is pivotable in the same direction aboutthe second axis to sequentially move each blister into alignment with ablister piercing member and to cause rotation of the blister piercingmember about the first axis so that the blister piercing memberpunctures the lid of an aligned blister.

The actuating mechanism may be configured such that rotation of theactuating lever about the second axis through a first portion of itsstroke moves a blister into alignment with a blister piercing memberand, further rotation of the actuating lever about the second axis inthe same direction, during a second portion of its stroke, causesrotation of the blister piercing member about the first axis so that theblister piercing member punctures the lid of an aligned blister.

The actuating mechanism may include a blister strip drive wheel and theactuating lever may be engaged with said blister strip drive wheelduring rotation of the actuating lever to rotate said blister stripdrive wheel and drive said strip.

In a preferred embodiment, the actuating mechanism is configured suchthat the actuating lever and blister strip drive wheel disengage at theend of the first portion of the stroke so that the blister strip drivewheel remains substantially stationary during rotation of the actuatinglever through said second portion of its stroke.

Preferably, the actuating mechanism comprises a drive coupling memberrotatable in response to rotation of the actuating lever to rotate theblister strip drive wheel, the blister strip drive wheel being rotatablymounted on said drive coupling member, wherein the actuating mechanismincludes means to control rotation of the blister strip drive wheelrelative to rotation of the drive coupling member so that the blisterstrip drive wheel rotates together with the drive coupling member duringthe first portion of the stroke of the actuating lever but not duringthe second portion of the stroke of the actuating lever.

In a preferred embodiment, the means for controlling rotation of theblister strip drive wheel is also configured to inhibit rotation of theblister strip drive wheel when the actuating lever is rotated in theopposite direction.

The drive coupling member may include a drive gear rotatable togetherwith the drive coupling member and the actuating lever can include adrive gear segment that drivingly engages with the drive gear member sothat the drive gear rotates in response to rotation of the actuatinglever to rotate the drive coupling to member.

Preferably, the means to control rotation of the blister strip drivewheel includes cooperating elements on the drive coupling member and onthe housing.

In an embodiment where the mouthpiece is pivotally mounted together withthe blister piercing element, one of the actuating lever and themouthpiece can have a drive cam element and the other of the actuatinglever and the mouthpiece can have a drive cam surface. The drive camelement cooperates with the drive cam surface so that the mouthpiecepivots about said first axis in response to rotation of the actuatingmember about the second axis to puncture the lid of an aligned blister.

The cam groove may have an arcuately shaped region having an axis thatcorresponds to the second axis about which the actuating lever rotatessuch that, during said initial rotation of the actuating lever throughits first portion of its stroke, the drive cam element slides along saidarcuately shaped region of the cam groove without causing rotation ofthe mouthpiece about the first axis.

In this embodiment, the cam groove can have a second region shaped suchthat, during further rotation of the actuating lever through its secondportion of its stroke, cooperation between the drive cam element and thesecond region of the cam groove causes the mouthpiece to rotate at thesame time as the actuating lever so that the blister piercing elementpunctures the lid of an aligned blister.

Alternatively, in the embodiment where the blister piercing element ispivotally mounted to a fixed housing, one of the actuating lever and theblister piercing member can have a drive cam element and the other ofthe actuating lever and the blister piercing member can have a drive camsurface. The drive cam element cooperates with the drive cam surface sothat the blister piercing element pivots about said first axis inresponse to rotation of the actuating member about the second axis topuncture the lid of an aligned blister.

The cam groove can have an arcuately shaped region having an axis thatcorresponds to the second axis about which the actuating lever rotatessuch that, during said initial rotation of the actuating lever throughits first portion of its stroke, the drive cam element slides along saidarcuately shaped region of the cam groove without causing rotation ofthe blister piercing member about the first axis.

The cam groove may have a second region shaped such that, during furtherrotation of the actuating lever through its second portion of itsstroke, cooperation between the drive cam element and the second regionof the cam groove causes the blister piercing element to rotate togetherwith the actuating so that the blister piercing element punctures thelid of an aligned blister.

In any of the embodiments, the inhaler may comprise a cap and a couplingpivotally mounting the cap to the housing for rotation about a thirdaxis, the cap covering the mouthpiece in a closed position.

The housing preferably comprises a shell and the actuating lever ismounted for rotation about the second axis on the shell and includes amounting plate that extends within a space between the shell and thecap.

In one embodiment, the actuating lever comprises a button extending fromsaid plate and protruding out of said space to enable actuation of theactuating lever by a user.

Preferably, the actuating lever comprises an arcuately shaped openingextending about the second axis, the coupling that pivotally mounts thecap to the housing extending through said opening so that the couplingtravels along the arcuately shaped opening as the actuating lever pivotsabout the second axis.

The cap and actuating lever may include cooperating means configuredsuch that, when the cap is rotated from its open position back into itsclosed position in which it covers the mouthpiece, the actuating leveris rotated rotate back into its initial position.

Preferably, the cooperating means comprises a wall on the actuatinglever and a drive member depending from the cap towards the actuatinglever, said wall and drive member being positioned between the secondand third axes such that the drive member engages the wall when the capis rotated in a direction back into its closed position to rotate theactuating member about the second axis back into its initial position.

In any embodiment, the inhaler may include a detent mechanism such as acantilevered arm on the actuating lever and a pawl on the shell, the armbeing resiliently deformed by said pawl as the actuating lever reachesthe end of the second portion of its stroke, to hold the actuating leverin position until the cap is closed.

The cantilevered arm preferably includes a kinked portion that snapsover the pawl when the actuating lever is rotated towards the endportion of its stroke.

In a preferred embodiment, a wall is slideably mounted in the housing todivide it into unused and used blister compartments.

The wall preferably comprises a baffle extending between opposinghousing walls and an elongate foot extending substantially atright-angles to the baffle and being slideably received within a recessin a surface of a wall of the housing.

The baffle is preferably attached to a central region of the foot.

In a preferred embodiment, the foot is widest at its ends remote fromthe baffle such that only the ends of said foot contact the walls ofsaid recess in the housing.

According to another aspect of the invention, there is provided aninhaler comprising a housing to receive a strip having a plurality ofblisters, each blister having a puncturable lid and containing a dose ofmedicament for inhalation by a user, a mouthpiece pivotally mounted tothe housing and through which a dose of medicament is inhaled by a userand an actuating mechanism including a lever operable to sequentiallymove each blister into alignment with a blister piercing memberdepending from the mouthpiece said actuating lever also being operableto cause the mouthpiece to pivot so that the blister piercing memberpunctures the lid of an aligned blister so that, when a user inhalesthrough the mouthpiece, an airflow through the blister is generated toentrain the dose contained therein and carry it, via the mouthpiece,into the user's airway.

A cap is preferably pivotally mounted to the housing that covers themouthpiece in a closed position.

The cap may extend over the actuating lever in a closed position.

In one embodiment, the actuating lever is pivotally mounted to thehousing and the actuating mechanism is configured such that theactuating lever is pivotable to sequentially move each blister intoalignment with a blister piercing member and also pivotable to causerotation of the mouthpiece so that the blister piercing member puncturesthe lid of an aligned blister.

The actuating lever is preferably pivotable in the same direction tosequentially move each blister into alignment with a blister piercingmember and to cause rotation of the mouthpiece so that the blisterpiercing member punctures the lid of an aligned blister.

The actuating mechanism may be configured such that an initial rotationof the actuating lever through a first portion of its stroke moves ablister into alignment with a blister piercing member and, furtherrotation of the actuating lever causes rotation of the mouthpiece sothat the blister piercing member punctures the lid of an alignedblister.

In a preferred embodiment, the actuating mechanism is configured suchthat movement of the strip stops between said initial and furtherrotation of the actuating lever.

The actuating mechanism preferably includes a blister strip drive wheelaround which a blister strip received in the housing is fed, saidblister strip drive wheel being rotatable in response to rotation of theactuating lever to drive said strip.

In one embodiment, wherein the blister strip drive member comprises aplurality of spokes extending from a hub, the spokes being spaced fromeach other such that a spoke locates between blister cavities as ablister strip passes around the blister strip drive member to engage anddrive a strip as the blister strip drive member rotates, the blisterstrip drive member being positioned relative to a wall such that thedistance between the hub and said wall is less than the height of ablister cavity such that onward rotation of the wheel causes a blistercavity to be at least partially squashed or sandwiched between the huband said wall.

The inhaler preferably includes a drive coupling member rotatable inresponse to rotation of the actuating lever, the blister strip drivewheel being rotatably mounted on said drive coupling member, the drivecoupling member and the housing including means to control rotation ofthe blister strip drive member relative to rotation of the drivecoupling member so that the blister strip drive wheel rotates togetherwith the drive coupling member during part of the rotation of the drivecoupling member in the same direction.

In one embodiment, the means for controlling rotation is configured sothat the blister strip drive wheel rotates together with the drivecoupling member during part of the rotation of the drive coupling memberin the same direction and the blister strip drive wheel does not rotateat all when the drive coupling member rotates in the opposite direction.

The drive coupling member may include a drive gear member and theactuating lever includes a drive gear segment that drivingly engageswith the drive gear member so that the drive gear member rotates inresponse to rotation of the actuating lever. The drive coupling memberand the drive gear member may be integrally formed as one component.

Preferably, the actuating lever includes a mouthpiece drive cam elementthat cooperates with a cam groove formed in the mouthpiece.

The cam groove in the mouthpiece can have an arcuately shaped regionsuch that, during said initial rotation of the actuating lever throughits first portion of its stroke, the drive cam element slides along thecam groove with substantially no rotation of the mouthpiece.

The cam groove may also have a second region shaped such that, duringfurther rotation of the actuating lever beyond the first portion of itsstroke, cooperation between the drive cam element and the cam groovecauses the mouthpiece to rotate together with the actuating lever topull the blister piercing element depending therefrom into the lid of analigned blister.

The cap and the actuating lever may be configured such that, when thecap is rotated from an open position back into its closed position, thecap cooperates with the actuating lever to cause it to rotate back intoits initial position.

Rotation of the actuating lever back into its initial position inresponse to rotation of the cap may also cause the drive cam element toslide back along the cam groove and lift the mouthpiece back into itsoriginal position in which the blister piercing element is removed fromthe aligned blister.

In a preferred embodiment, the cap includes a drive pin that cooperateswith the actuating lever during closure of the cap so that the actuatinglever is also rotated back to its initial position.

The actuating lever may have a hole therethrough and the drive pinextends from the cap into said hole, the drive pin engaging with thesidewall of said hole when the cap is rotated from its open into itsclosed position.

In one embodiment, the housing comprises a shell that defines a chamberto receive a blister strip, the blister strip drive wheel being receivedin the shell, the shell having opposing end walls spaced from each otherby a side wall, the drive coupling member extending through a hole inone of said opposing end walls such that the drive gear is disposed onthe outside of the shell.

The actuating member may comprise a plate extending between an actuatingbutton and the gear segment, said plate extending across a surface of anend wall on the outside of the shell.

The actuator can be pivotally mounted to a hub upstanding from saidsurface.

The actuating member may also comprise a second plate that extendsparallel and spaced from the first plate, the shell being receivedbetween said plates and said second plate being pivotally mounted to ahub upstanding from the surface of said opposite end wall of the shell.

In one embodiment, the mouthpiece has a peripheral wall that extendsacross the surface of the outside of the shell.

The actuating lever may include an actuating button that extends betweensaid plates and across the side wall of the shell.

The cap can have parallel side wall sections spaced from each other byan intermediate section, the side wall sections each extending across acorresponding end wall of the shell, one of said side wall sections ofthe cover enclosing the first and second plates of the actuating leverand at least a portion of the side wall of the mouthpiece.

The intermediate section may extend across the side wall of the shelland covers the mouthpiece in a closed position.

In one embodiment, a boss upstands from opposite surfaces of the shelleach of which locate in a recess in a corresponding side wall section ofthe cap to pivotally mount the cap to the shell.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of exampleonly, with reference to FIGS. 3 to 16 of the accompanying drawings, inwhich:

FIGS. 1 and 2 are side views of a conventional inhalation device to showhow a strip is driven to sequentially move blisters into alignment witha blister piercing element by movement of an actuator from the positionshown in FIG. 1 to the position shown in FIG. 2 which drives an indexingwheel. A piercing head on the actuator pierces the lid of an alignedblister when the actuator is returned to its normal position, as shownin FIG. 1;

FIGS. 3 a to 3 e is a sequence of drawings to show the general functionand operation of the inhaler according to the invention;

FIG. 4 is a side elevation of an inhalation device according to anembodiment of the invention;

FIG. 5 is the side elevation of FIG. 4, but with the cap removed so thatthe internal components can be seen;

FIG. 6 is the side elevation of FIG. 5 after removal of one-half of theshell forming the housing of the inhaler;

FIG. 7 is an exploded perspective view showing the individual componentsof the inhaler according to the invention.

FIG. 8 is a partial perspective view of the blister strip indexingmechanism for use in the inhaler of the invention;

FIG. 9 is a partial perspective view of the blister strip indexingmechanism shown in FIG. 8 following partial rotation of the actuatinglever into an intermediate position from its home position;

FIG. 10 is the same view as shown in FIG. 9, but without the optionalcantilevered chassis arm;

FIG. 11 is a partial perspective view of the blister strip indexingmechanism shown in FIGS. 8 to 10, after the actuating lever has beenrotated to a point at which drive between the drive coupling and theactuator has disengaged;

FIG. 12 is a partial perspective view of the opposite side of theindexing mechanism shown in FIGS. 9 to 11;

FIG. 13 a is a perspective view of the drive coupling used in theindexing mechanism of the inhaler shown in FIGS. 9 to 12;

FIG. 13 b is a side view of the drive coupling illustrated in FIG. 13 ain which the flexible flange portion has been deflected in a direction“T” towards the shaft or, towards an indexing wheel mounted on thatshaft.

FIG. 14 is a partial view of the inhaler according to the inventionshowing the form and position of the indexing wheel that may be used inorder to crush used blisters as they pass around the indexing wheel;

FIG. 15 is an exploded perspective view showing the individualcomponents of the inhaler according to another embodiment of theinvention; and

FIG. 16 is a cross-sectional side view of the inhaler shown in FIG. 15.

DETAILED DESCRIPTION

Referring now to FIGS. 3 a to 3 e of the accompanying drawings, there isshown an inhaler 10 having a housing 11 formed from two shell portions11 a, 11 b (see FIGS. 6 and 7), a cap 12 pivotally mounted to thehousing 11 for rotation about an axis marked “C” (see FIGS. 5 to 7) froma closed position as shown in FIG. 4 in which the cap 12 covers andprotects a mouthpiece 13 to a fully open position, as shown in FIGS. 3(b) to 3(d) and in a direction indicated by arrow “R” in FIG. 3( a), inwhich the mouthpiece 13 is exposed to enable a user to inhale a dose ofmedicament through the mouthpiece 13.

It should be noted that the cap is ‘passive’ in the sense that it can beopened and closed freely without performing the function of indexing ofthe blister strip or causing a blister piercing member 15 depending fromthe mouthpiece 13 to pierce the lid of an aligned blister.

The cap 12 is rotated into its fully open position in the direction ofarrow “R”. An actuating lever 14 is revealed as soon as the cap 12 isrotated out of its closed position. The user then applies pressure tothe actuating lever 14, so that it rotates in the direction indicated byarrow “S” in FIG. 3( b).

During initial rotation of the actuating lever 14 through a firstportion of its stroke into the position as it is shown in FIG. 3( b),the strip is indexed so as to move an unused blister into alignment withthe blister piercing member 15.

When the actuating member is rotated through a second portion of itsstroke beyond the position shown in FIG. 3( b) and after havingcompleted the first portion of its stroke, in the direction of arrow “T”in FIG. 3( c), the strip remains stationary but the mouthpiece 13 is nowpivoted so that the blister piercing member 15 pierces the lid of thepreviously aligned blister.

Although reference is made to a blister piercing member 15, it will beappreciated that multiple openings are formed in the lid of the blisterso that air can be drawn into the blister through one or some of thoseopenings and flow out of the blister together with an entrained dose ofmedicament, through one or more other openings and via the mouthpieceinto a patient's airway.

Once the actuating lever is in the position shown in FIG. 3( c), theuser now inhales through the mouthpiece 13, as shown by arrows indicatedby “U” in FIG. 3( d).

After inhalation, the user rotates the cap in the opposite direction,i.e. in the direction indicated by “V” in FIG. 3( e). During thismovement, the cap 12 engages with the actuating lever 14 so that theactuating lever 14 also returns to its initial position as shown in FIG.3( a), the strip remaining stationary during this return movement of theactuating lever 14.

As mentioned above, the cap 12 is passive, although it does perform thefunction of re-setting the actuating member back to its originalposition in the event that the actuating lever is depressed prior toclosing the cap.

As previously mentioned, the inhaler of the invention has an indexingmechanism that has previously been described with reference toWO2009/092652 A1. This aspect of the inhaler of the invention will nowbe described in detail with reference to FIGS. 8 to 13 a. Although thedrawings show a slightly different arrangement, in which an actuator 54takes the place of a drive gear 16 attached to the drive coupling member57 in the present invention, the principle remains the same as theactuator 54 and the drive gear are both rotated to index the strip.Therefore, rotation of the drive gear 16 performs the same function asrotation of the actuator 54 referred to in the description of FIGS. 8 to13 a below.

Referring now to FIG. 8, there is shown a partial perspective view of aninhalation device 50 comprising an indexing mechanism 51.

The indexing mechanism 51 includes an indexing wheel 55 comprising fourvanes 55 a,55 b,55 c,55 d, each having an enlarged head portion 56 a,56b,56 c,56 d. As is clear from reference to FIGS. 1 and 2, once a blisterstrip (not shown in FIGS. 8 to 14) has passed over the blister locatingchassis 53, it passes around the indexing wheel 55. A blister locates inthe space between two vanes 55 a,55 b,55 c,55 d so that, as the indexingwheel 55 rotates in response to rotation of the actuator 54, a vane 55a,55 b,55 c,55 d engages a blister located between the vanes 55 a,55b,55 c,55 d so as to drive the strip around the indexing wheel 55 tosequentially move each blister forward by a sufficient distance to movea fresh blister into alignment with a blister piercing element.

The indexing mechanism 51 includes a drive coupling member 57 (mostclearly shown in FIGS. 13 a and 13 b) for selectively or temporarilycoupling the actuator 54 to the indexing wheel 55 so that, when coupled,the indexing wheel 55 rotates in response to rotation of the actuator 54to index the strip. The drive coupling member 57 comprises a shaft 58defining an axis of rotation “A” (see FIGS. 13 a and 13 b) on which theindexing wheel 55 is rotatably received so that it can rotate freelyabout the shaft 58 about said axis of rotation “A”. The actuator 54 isfixedly attached to the drive coupling member 57 (the gear drive wouldalso be fixedly attached to the drive coupling member 57) so that thedrive coupling member 57 rotates together with the actuator 54 at alltimes. In the embodiment illustrated and described with reference toFIGS. 8 to 12, the actuator 54, drive coupling member 57 and indexingwheel 55 are all mounted coaxially for rotation about the same axis “A”.However, it will be appreciated that in the embodiment of FIG. 7, themouthpiece 13 and actuating lever 14 are not coaxially mounted with Axis‘A’.

The drive coupling member 57 has a circular flange 59 that extendsradially from one end of the shaft 58. A portion 60 of the flange iscut-away (see arcuate opening 61 in FIG. 8) over an angle ofapproximately 180 degrees where the flange 59 joins the shaft 58 so thatthis portion 60 of the flange 59 is not directly attached to the shaft58 but only to the remaining portion of the flange 59 at each of itsends 60 a,60 b. As a result, this portion 60 of the flange 59 isflexible relative to the rest of the flange 59 and can be deflected outof the plane of the flange 59 that extends at right angles to the axisof the shaft, in an axial direction (indicated by “T” and “S”, in FIG.13 b) either towards or away from the shaft 58 or, more importantly,towards or away from the indexing wheel 55 which is mounted on the shaft58, when force is applied to it. This flexible flange portion 60 hingesabout an axis B which intersects the axis A of the shaft 58 and actuator54 but extends at right angles to it. The drive coupling member 57, orat least the flange 59, is made from a resilient material so that whenthe deflected flexible flange portion 60 is released, it returns to itsneutral, unstressed position, in which it lies coplanar with theremaining fixed portion of the flange 59.

The flexible flange portion 60 has an integrally formed flangedeflecting dog 62 projecting radially from its circumferential edge. Theflange deflecting dog 62 has first and second angled engaging faces63,64 on opposite sides. When the drive coupling member 57 is rotated inresponse to rotation of the actuator 54 in one direction, one of thefirst or second angled engaging faces 53,54 cooperate with a fixedformation 65 on the housing 52 to cause the flexible flange portion 60to deflect in a first direction. When the drive coupling member 57 isrotated in the opposite direction, the other angled engaging facecooperates with the formation 65 on the housing 52 to cause the flexibleflange portion 60 to deflect in a second, opposite direction, as will beexplained in more detail below.

The flexible flange portion 60 also has an arcuately shaped indexingwheel drive dog 66 that upstands in an axial direction from its surfacetowards the indexing wheel 55 in the same direction as the shaft 58 andextends partially around the circumference of the flexible flangeportion 60. As will now be explained in more detail below, an end face66 a (see FIG. 13 a) of the indexing wheel drive dog 66 engages a vane55 a,55 b,55 c,55 d of the indexing wheel 55 when the flexible flangeportion 60 has been deflected in a first direction, as indicated byarrow “T” in FIG. 13 b (the flange portion 60 is shown in its deflectedposition in FIG. 13 b), so that the indexing wheel 55 is driven togetherwith the drive coupling member 57.

As mentioned above, the flange deflecting dog 62 engages a formation 65on the housing 52 when the drive coupling member rotates in response torotation of the actuator 54 so as to flex the deflectable portion 60 ofthe flange 59. This formation 65 comprises first and second arcuatelyshaped tracks or paths 67, 68 positioned one above the other or spacedfrom each other in the axial direction. The surface of the innermosttrack 67 is visible in FIG. 8. The lower or outermost track 68 islocated beneath it and is visible in FIG. 12. The ends of the tracks 67a, 68 a have angled faces for reasons that will become apparent.

When the actuator 54 (or the drive gear) is rotated in a firstdirection, the drive coupling member 57 rotates together with it and thefirst outwardly facing angled surface 63 on the flange deflecting dog 62contacts the angled face 67 a of the innermost track 67. Furtherrotation of the drive coupling member 57 causes the flange deflectingdog 62 to ride up onto the surface of the innermost track 67 therebydeflecting the flexible flange portion 60 inwardly, i.e. in a directioninto the housing 62 or towards the shaft 58 and the indexing wheel 55.

When the flexible flange portion 60 has been deflected inwardly in thedirection of arrow T, further rotation of the drive coupling member 57causes the indexing wheel drive dog 66 to engage a vane, which as shownin FIG. 8 is vane 55 c, of the indexing wheel 55 so that the indexingwheel 55 rotates together with the drive coupling member 57 and drive tothe indexing wheel 55 is engaged.

When the end of the innermost track 67 has been reached, the flangedeflecting dog 62 falls off the surface of the track 67 and theresilience of the flexible flange portion 60 causes it to return to itsoriginal unstressed or neutral position. When the drive coupling member57 is rotated further, the indexing wheel drive dog 66 no longer engageswith the vane 55 c of the indexing wheel 55 and instead passes beneathit so the indexing wheel 55 remains stationary. Therefore, drive to theindexing wheel 55 is disengaged, despite continued rotation of theactuator 54 in the same direction.

When the actuator 54 is rotated back in the opposite direction towardsits home position, the second inwardly facing angled surface 64 of theflange deflecting dog 62 now contacts the lower or outermost track 68 sothat the flange deflecting dog 62 now rides onto the surface of thatsecond track 68, thereby causing the flexible flange portion 60 todeflect outwardly or in the opposite direction to the direction in whichit was previously deflected. Engagement of the flange deflecting dog 62with the outermost track 68 so as to deflect the flange portion 60 inthe opposite direction, enables the drive coupling member 57 to rotatein the opposite direction without any drive to the indexing wheel 55. Itwill be appreciated that, if the flange portion 60 was not deflected inthe opposite direction, the flange deflecting dog 62 would simply engageagainst the end of the formation 65 in the housing 62 when rotated backin the opposite direction, thereby preventing rotation in the oppositedirection or, the flange deflecting dog 62 would travel back over theinnermost track 67 deflecting the flexible flange portion 60 in the samedirection causing the opposite end 66 b of the indexing wheel drive dog66 to engage with a vane 65 b of the indexing wheel 65 thereby drivingthe indexing wheel 65 backwards rather than leaving it stationary withno drive engaged. Therefore, it is necessary to ensure that the flexibleflange portion 60 is deflected in the opposite direction so that thereis no drive to the indexing wheel during rotation of the coupling member67 in the opposite direction.

When the drive deflecting dog 62 reaches the end of the outermost track68, the flexible flange portion 60 returns to its original unstressed orneutral position, due to its resilience.

It will be appreciated that the extent of rotation of the indexing wheel55 relative to the extent of rotation of the actuator 54 may becontrolled by altering the circumferential length of the inner and outertracks 67,68. If the tracks are made longer, the flexible flange portion60 will be deflected for a greater proportion of the angle through whichthe actuator 54 is rotated and so the indexing wheel drive dog 66 willbe engaged with the indexing wheel 55 to rotate the indexing wheel 55throughout that angle. If required, the tracks 67,68 could be madesufficiently long so that the indexing wheel 55 rotates during rotationof the actuator 54 through its entire angle of movement in onedirection. Alternatively, the tracks 67,68 could be made shorter toreduce the angle through which the actuator 54 and indexing wheel 55rotate together. Ideally, the track length can be selected so that theindexing wheel 55 is rotated through a sufficient angle to move thenext, unused blister, into alignment with the blister piercing element.

The further rotation of the actuator 54 (the gear drive) causes themouthpiece to rotate so that the blister piercing member pierces the lidof a blister that has just been moved into alignment with the blisterpiercing element.

It will be appreciated that the indexing mechanism 51 is designed toenable a stroke to be aborted when the actuator 54 or cap has beenrotated through an angle which is sufficient to cause initial indexingof the strip but which is not such that the drive to the indexing wheel55 has disengaged, i.e. a position in which the flange drive dog 62 hasnot reached the end of the innermost track 67. If the stroke is abortedand the actuator 54 returned to its original position before drive tothe indexing wheel 55 has disengaged (or the drive gear rotated back toits initial position), the strip will be driven backwards into itsoriginal position as a rear surface 66 b of the indexing wheel drive dog66 will engage a preceding vane 55 b to drive the indexing wheel 55 inthe opposite direction.

The indexing mechanism 51 also includes optional means for locking theindexing wheel 55 to prevent its rotation between indexing steps andmeans for temporarily releasing that lock to allow rotation of theindexing wheel 55 when driven by the indexing wheel drive dog 66. Thelock also improves positional accuracy of the strip and, morespecifically, the next blister to be pierced. This locking arrangementwill now be described in more detail below, although it should be notedthat the locking mechanism can be omitted altogether.

The blister location chassis 53 may optionally comprise a resilientlyflexible cantilever arm 70 that extends from the body 53 of the chassistowards the indexing wheel 55. The free end of the cantilever arm 70 hasan enlarged head portion 71 comprising a letterbox shaped slot, windowor opening 72 in which the head 56 c of a vane 55 c of the indexingwheel 55 is located. The opening 72 is dimensioned such that the head 56c of the vane 55 c (as shown in FIG. 8) is a snug fit therein so thatrotation of the indexing wheel 55 is prevented. In the normal or homeposition of the actuator 54, the head 56 c of a vane 55 c is located insaid opening 72 in the cantilever arm 70 of the chassis 53 so thatrotation of the indexing wheel 55 is prevented.

When the actuator 54 is rotated and the flange drive dog 62 engages theinnermost track 67 so as to deflect the flexible portion of the flange60 inwardly towards the indexing wheel 55, the indexing wheel drive dog66 initially engages with a protrusion 71 a extending from an inner sideof the enlarged head 71 on the cantilever arm 70 of the chassis 53 sothat the cantilever arm 70 is deflected outwardly, away from theindexing wheel 55, to free the head 56 c of the vane 55 c from the slot72, thereby unlocking the indexing wheel 55. Only once the indexingwheel 55 has been released by the indexing wheel drive dog 66 pushingthe cantilever arm 70 away from the indexing wheel 55 does the indexingwheel drive dog 66 subsequently engage a vane 55 c of the indexing wheel55 so that further rotation of the drive coupling member 57 rotates theindexing wheel 55.

Prior to the flange drive dog 62 falling off the end of the innermosttrack 67 and the flexible flange portion 60 returning to its undeflectedstate due to its resilience, the indexing wheel drive dog 66 no longerpushes against the cantilever arm 70 and so the cantilever arm 70 isfree to move back towards the indexing wheel 55. As the cantilever arm70 is free to move back just prior to rotation of the indexing wheel 55being completed, the cantilever arm is prevented from moving all the wayback by the head 56 b of a following vane 55 b which contacts thecantilever arm 70. During further rotation of the indexing wheel, thehead 56 b slides across the cantilever arm and then drops into theopening 72 thereby allowing the cantilever arm 70 to move all the wayback and locking the indexing wheel 55 in position prior to any furtherrotation of the drive coupling member 57 in response to continuedrotation of the actuator 54.

On the return stroke of the actuator 54, it will be appreciated thatdeflection of the flexible flange portion 60 in the opposite direction,i.e. in a direction away from the indexing wheel, also ensures that theindexing wheel drive dog 66 clears the chassis arm 70 and so theindexing wheel 55 is not unlocked, thereby preventing any rotation ofthe indexing wheel 55 during the return stroke.

The blister strip drive member or indexing wheel 15 of the invention maytake a slightly different form to that described with reference to FIGS.8 to 13 b, although the principle still remains the same. In particular,the indexing wheel 15 may be used to squeeze the used blister cavitiesas they pass around it, thereby at least partially crushing them. Thisis achieved by enlarging the axle or hub 18 of the indexing wheel sothat the distance (X in FIG. 14) between the hub and the casing or wallof the device 11, or a component fixed to the casing 11, is less thanthe maximum height of a blister cavity. As the blister cavities areentrained between the spokes 17 a of the indexing wheel 17, onwardrotation of the wheel 17 causes the cavities to be at least partiallysquashed or sandwiched between the enlarged hub 18 of the indexing wheel17 and the casing 11 of the device. The advantage of at least partiallycrushing the empty blister cavities is that they then take up less spacewhen coiled within the used blister chamber of the device as the coiledstrip has a smaller diameter. Furthermore, a natural curvature isimparted to the strip, both as a result of being fed around the blisterdrive wheel and also as a result of the crushing of the blistercavities. This encourages the used portion of the strip to coil morereadily. It is also apparent that, when the blister cavities have beencrushed, the cavity is more resilient to denting at the point at whichthe spoke of the blister drive wheel contacts the strip, i.e. at theroot where the blister cavity meets the remainder of the strip.Therefore, a more positive and precise drive of the strip is achievedwhen the blisters have been crushed.

As mentioned above, the drive coupling member 57 of the inhaler of thepresent invention is modified in that the drive gear 16 is attachedthereto in place of the actuator 54 so that the drive coupling member 57rotates in response to rotation of the drive gear 16. It is alsoenvisaged that the drive gear 16 may be moulded integrally with thedrive coupling member 57.

It will be apparent from FIG. 7, that the drive coupling member 57extends into an opening 19 in a side wall of the shell 11 b of thehousing 11 and the drive gear 16 is coupled thereto so that it isdisposed on the outside surface of said side wall, only the drivecoupling member 57, the blister strip drive wheel 17 and the blisterstrip itself, being received within the housing between the shellportions 11 a, 11 b.

The actuating lever 14 has a first plate-like portion 20 that extendsacross the outside surface of the shell lib and has a hole 21 therein toreceive a boss 22 upstanding from said surface, to pivotally mount theactuating lever 14 to the shell 11 for rotation about a second axis (A-Ain FIGS. 7 and 15). The actuating lever 14 may also have a secondplate-like portion 23 that is parallel to and spaced from the firstportion 20 by an actuating button 24. The second plate-like portionextends across the opposite surface of the shell 11 a and also has ahole 25 to engage with a corresponding boss upstanding from saidopposite surface so as to pivotally couple the actuating member 14 tothe shell 11 with the actuating button extending between the plates20,23 and opposite surfaces of the shell portions 11 a, 11 b.

The first plate 20 has a further aperture 26 therein and the cap 12 ispivotally mounted to the outer shell portion 11 b by a coupling such asa boss 80 upstanding from a surface of the shell portion 11 b thatlocates in a corresponding recess (not shown in FIG. 7, but see hole 92in FIG. 15) in the cap 12, for rotation of the cap 12 about a thirdaxis. The boss 80 extends through the aperture 26 in the actuatingmember 14. The aperture 26 is arcuately-shaped and has the second axisas its centre so that, when the actuating lever 14 is rotated about thesecond axis, the boss 80 travels within the aperture 26 without engagingthe actuating member 14, and so the cap 12 remains stationary. Theactuately-shaped aperture 26 acts as a clearance hole for the pivotalattachment of the cap 12 to the shell 11 b and so as to allow rotationof the actuating lever 14 about the second axis.

A drive member (not shown) extends from an inner surface of the cap 12.The drive member is located between, and spaced from, each of the secondand third axes and extends towards the actuating lever 14 and theactuating lever 14 includes a wall 27 for engagement by said drivemember when the cap 12 is rotated it about its third axis back towardsits closed position and after the actuating member 14 has been rotatedabout its second axis. The drive member and wall 27 meet at a locationbetween the second and third axes so that, upon further rotation of thecap 12 back towards its closed position, the drive member pushes againstthe wall 27. Pressure of the drive member against the wall 27 causes theactuating member 14 to rotate back into its original position, togetherwith the cap 12 into its closed position.

The cap 12 and actuating lever 14 are configured so that, when the cap12 is in its closed position and the actuating lever 14 has returned toits initial position, the cap 12 overlies the actuating button 24 whichis pressed by a user to operate the device. This prevents a user fromattempting to operate the device by rotating the actuating member 14prior to opening the cap 12.

The actuating member 14 has a gear segment 28 that drivingly meshes withthe gear drive 16 so that rotation of the actuating member 14 alsocauses rotation of the gear drive 16 and selective rotation of theblister strip drive member relative to the gear drive 16 whilst theactuating member 14 is rotated through the initial portion of itsstroke, due to the indexing mechanism described above, so that theblister strip is initially driven to move the next blister intoalignment with the blister piercing member 15. During further rotationof the actuating member 14 through the second portion of its stroke, theblister strip is prevented from moving as the drive coupling member 57is de-coupled from the blister strip drive wheel 17. During rotationthrough the second portion of its stroke, the blister piercing member 15carried by the mouthpiece 13 is rotated so that it pierces the aligned,and now stationary, blister.

A cam drive member (not shown) extends from the first plate 20 towardsthe second plate 23. The cam drive member is received in a cam groove orslot 29 formed in a peripheral wall 30 depending from the mouthpiece 13.As is apparent from FIG. 7, the cam groove or slot 29 has an arcuateportion 29 a followed by a leg portion 29 b at one end. It will beappreciated that the slot 29 may alternatively be provided in theactuating lever 14 and the cam drive member may extend from themouthpiece 13 to achieve the same function.

During initial rotation of the actuating member 14 through the firstportion of its stroke, the cam drive member slides along the arcuateportion 29 of the cam slot 29 without causing any movement of themouthpiece 13, as the arcuate portion 29 a of the cam slot 29 has thesecond axis as its radius. However, during subsequent rotation of theactuating member 14, the cam member reaches the leg portion 29 b of thecam slot 29 and engages the side walls of the cam groove 29 so as tocause the mouthpiece 13 to rotate about a first axis B-B together withthe actuating member 14 thereby pulling the blister piercing member 15,depending from the mouthpiece 13, into the aligned blister.

Although reference is made to a pivoting mouthpiece 13, it will also beappreciated that, in an alternative embodiment, the blister piercingmember 15 may be pivotally attached to a mouthpiece 13 or mounted in asupport or module that is pivotally attached to the mouthpiece 13. Inthese embodiments, the mouthpiece 13 itself remains stationary so that,in response to operation of the actuating member 14, the blisterpiercing member 15 pivots relative to the stationary mouthpiece 13 topuncture the lid of an aligned blister.

During rotation of the cap 12 from its open to its closed position,rotation of the actuating member 14 due to rotation of the cap 12 alsocauses rotation of the mouthpiece back to its original position as thecam member travels back along the cam slot 29 b.

As shown in FIG. 7, a spiral element 31 is also optionally mountedwithin the housing 11 into which the used portion of the strip is fed.

Although a region is provided within the housing 11 to receive the usedportion of the strip, it will be appreciated that the invention is alsoapplicable to other inhalation devices (not shown) in which usedblisters are not retained within the housing 11 but pass out through anopening (not shown) in the wall of the housing 11 for periodicdetachment by a user.

Although piercing of an aligned blister only occurs after movement ofthe strip has stopped, it is envisaged that the mechanism could beconfigured so that de-coupling of the blister strip drive wheel 17 andthe drive coupling member 57 only occurs after the blister piercingelement 15 has pierced, or begun to pierce, the lid of a blister so thatthe piercing element is drawn across and through the lid of the blisteras it enters it. This creates a larger hole relative to the size of holecreated when the strip is stationary prior to being puncturing by theblister piercing element. A larger hole can advantageously ensure thatall the drug dose is entrained and removed from the blister.

A modified embodiment is shown in FIGS. 15 and 16. This embodiment issimilar to the previous embodiment and functions in the same way butadditionally includes a detent mechanism for holding the actuating lever81 at the end of its stroke so that a small force must be applied to itto overcome the hold placed on it by the detent mechanism and allow theactuating lever 81 to return to its initial position. The detentmechanism includes a cantilever 82 that extends from the actuating lever81 and has a kinked region 82 a which engages with a pawl 83 on theshell portion 84 b as the actuating lever 81 approaches the end of thesecond portion of its stroke, so that the cantilever 82 is resilientlydeformed and as it rides over the kinked region 82 a and springs back toits original shape once the pawl 83 has cleared the kinked region 82 a.When the actuating lever 81 is rotated back towards its initialposition, sufficient force must initially be applied to the actuatinglever 81 so that the cantilever 82 is deformed by the pawl 83 and ridesback over it. In addition to providing a slight resistance to initialmovement of the actuating lever 81, it also generates an audible ‘click’as the end of the second portion of the stroke of the actuating lever 81is reached and so provides an audible signal to the user that the end ofthe travel of the actuating lever 81 has been reached.

This embodiment also includes a rigid dividing wall 85 that separatesthe interior of the housing into an unused and used blister chamber86,87 (see FIG. 16). The wall 85 is slideably mounted within the shellportion 84 a of the housing so that, as more of the blisters are used,the force of the used coil of blisters in the used blister chamber 86presses against the wall 85 and pushes it in the direction indicated byarrow ‘P’ in FIG. 16, to enlarge the space for the used blisters andreduce the space previously occupied by the unused blisters.

The sliding wall 85 comprises an elongate foot 88 which is attached toand integrally formed with a baffle 89 that divides the compartment. Anapproximate central region 88 a of the foot 88 is attached to the baffle89 so that it extends in opposite directions on either side of thebaffle 89. The foot 88 is slideably received in a recess 90 formed in awall of the housing and is wider at its ends 88 b than in its centre 88a where it joins the baffle 89 so that contact with the walls of therecess 90 is primarily made with the wider ends 88 b of the foot 88.

A deeper, narrower recess 91 may extend deeper into the wall within thefirst recess 90 to receive a strengthening rib (not shown) dependingfrom the underside of the foot 88.

Many modifications and variations of the invention falling within theterms of the following claims will be apparent to those skilled in theart and the foregoing description should be regarded as a description ofthe preferred embodiments of the invention only. For example, althoughreference is made to a “mouthpiece”, the invention is also applicable todevices in which the dose is inhaled through the nasal passages.Therefore, for the purposes of this specification, the term “mouthpiece”should also be construed so as to include within its scope a tube whichis inserted into the nasal passages of a patient for inhalationtherethrough.

Furthermore, although the blister piercing member 15 is described asbeing attached to the mouthpiece so that the mouthpiece 13 and theblister piercing member rotate together, it is also envisaged that themouthpiece itself could remain stationary and the blister piercingelement 15 could be pivotally mounted to the mouthpiece 13 so that theblister piercing member 15 rotates relative to the mouthpiece 15 topierce the lid of an aligned blister.

In another embodiment, the cap and the actuating member could becombined into a single component so that rotation of the cap also causesindexing of the strip and piercing of an aligned blister.

It will be appreciated that the inhaler of the invention may be either apassive or active device. In a passive device, the dose is entrained ina flow of air caused when the user inhales through the mouthpiece.However, in an active device, the inhaler would include means forgenerating a pressurised flow of gas or air through the blister toentrain the dose and carry it out of the blister through the mouthpieceand into the user's airway. In one embodiment, the inhaler may beprovided with a source of pressurised gas or air within the housing.

The invention claimed is:
 1. An inhaler comprising a housing to receivea strip having a plurality of blisters, each blister having apuncturable lid and containing a dose of medicament for inhalation by auser, a mouthpiece mounted to the housing and through which a dose ofmedicament is inhaled by a user, a blister piercing member mounted forrotation about a first axis and an actuating mechanism including anactuating lever mounted for rotation about a second axis to sequentiallymove each blister into alignment with the blister piercing member,wherein the actuating lever cooperates with the blister piercing memberso that the blister piercing member pivots about said first axis inresponse to rotation of the actuating member from an initial positionabout the second axis to puncture the lid of an aligned blister so anairflow through the blister is generated to entrain the dose containedtherein and carry it, via the mouthpiece, into the user's airway when auser inhales through the mouthpiece; wherein the housing comprises ashell and the actuating lever is mounted for rotation about the secondaxis on the shell and includes a mounting plate that extends within aspace between the shell and a cap, the cap covering the mouthpiece in aclosed position.
 2. An inhaler according to claim 1, wherein the blisterpiercing member is immovably attached to the mouthpiece and themouthpiece is pivotally mounted to the housing so that the mouthpiecepivots, together with the blister piercing member, about said first axisin response to rotation of the actuating lever about the second axis. 3.An inhaler according to claim 1, wherein the actuating mechanism isconfigured such that the actuating lever and blister strip drive wheeldisengage at the end of the first portion of the stroke so that theblister strip drive wheel remains substantially stationary duringrotation of the actuating lever through said second portion of itsstroke.
 4. An inhaler according to claim 3, wherein the actuatingmechanism comprises a drive coupling member rotatable in response torotation of the actuating lever to rotate the blister strip drive wheel,the blister strip drive wheel being rotatably mounted on said drivecoupling member, wherein the actuating mechanism includes means tocontrol rotation of the blister strip drive wheel relative to rotationof the drive coupling member so that the blister strip drive wheelrotates together with the drive coupling member during the first portionof the stroke of the actuating lever but not during the second portionof the stroke of the actuating lever.
 5. An inhaler according to claim4, wherein said means for controlling rotation of the blister stripdrive wheel is also configured to inhibit rotation of the blister stripdrive wheel when the actuating lever is rotated in the oppositedirection.
 6. An inhaler according to claim 4, wherein the drivecoupling member includes a drive gear rotatable together with the drivecoupling member and the actuating lever includes a drive gear segmentthat drivingly engages with the drive gear so that the drive gearrotates in response to rotation of the actuating lever to rotate thedrive coupling member.
 7. An inhaler according to claim 4, wherein themeans to control rotation of the blister strip drive wheel includescooperating elements on the drive coupling member and on the housing. 8.An inhaler according to claim 1, wherein the blister piercing member isimmovably attached to the mouthpiece and the mouthpiece is pivotallymounted to the housing so that the mouthpiece pivots, together with theblister piercing member, about said first axis in response to rotationof the actuating lever about the second axis and wherein one of theactuating lever and the mouthpiece has a drive cam element and the otherof the actuating lever and the mouthpiece has a drive cam surface,wherein the drive cam element cooperates with the drive cam surface sothat the mouthpiece pivots about said first axis in response to rotationof the actuating member about the second axis to puncture the lid of analigned blister.
 9. An inhaler according to claim 8, wherein the drivecam surface includes a cam groove, the cam groove having an arcuatelyshaped region having an axis that corresponds to the second axis aboutwhich the actuating lever rotates such that, during said initialrotation of the actuating lever through a first portion of its stroke,the drive cam element slides along said arcuately shaped region of thecam groove without causing rotation of the mouthpiece about the firstaxis.
 10. An inhaler according to claim 9, wherein the cam groove has asecond region shaped such that, during further rotation of the actuatinglever through a second portion of its stroke, cooperation between thedrive cam element and the second region of the cam groove causes themouthpiece to rotate together with the actuating lever so that theblister piercing element punctures the lid of an aligned blister.
 11. Aninhaler according to claim 1, comprising a coupling pivotally mountingthe cap to the housing for rotation about a third axis.
 12. An inhaleraccording to claim 1, wherein the actuating lever comprises a buttonextending from said plate and protruding out of said space to enableactuation of the actuating lever by a user.
 13. An inhaler according toclaim 1, wherein the actuating lever comprises an arcuately shapedopening extending about the second axis, the coupling that pivotallymounts the cap to the housing extending through said opening so that thecoupling travels along the arcuately shaped opening as the actuatinglever pivots about the second axis.
 14. An inhaler according to claim13, wherein the cap and actuating lever include cooperating meansconfigured such that, when the cap is rotated from its open positionback into its closed position in which it covers the mouthpiece, theactuating lever is rotated back into its initial position.
 15. Aninhaler according to claim 14, wherein the cooperating means comprises awall on the actuating lever and a drive member depending from the captowards the actuating lever, said wall and drive member being positionedbetween the second and third axes such that the drive member engages thewall when the cap is rotated in a direction back into its closedposition to rotate the actuating member about the second axis back intoits initial position.
 16. An inhaler according to claim 1, comprising adetent mechanism including a cantilevered arm on the actuating lever anda pawl on the shell, the arm being resiliently deformed by said pawl asthe actuating lever reaches the end of the second portion of its stroke,to hold the actuating lever in position until the cap is closed.
 17. Aninhaler according to claim 16, wherein the cantilevered arm includes akinked portion that snaps over the pawl when the actuating lever isrotated towards the end portion of its stroke.
 18. An inhaler accordingto claim 1, wherein the actuating lever is pivotable in the samedirection about the second axis to sequentially move each blister intoalignment with a blister piercing member and to cause rotation of theblister piercing member about the first axis so that the blisterpiercing member punctures the lid of an aligned blister.
 19. An inhaleraccording to claim 18, wherein the actuating mechanism is configuredsuch that rotation of the actuating lever about the second axis througha first portion of its stroke moves a blister into alignment with ablister piercing member and, further rotation of the actuating leverabout the second axis in the same direction, during a second portion ofits stroke, causes rotation of the blister piercing member about thefirst axis so that the blister piercing member punctures the lid of analigned blister.
 20. An inhaler according to claim 19, wherein theactuating mechanism includes a blister strip drive wheel, wherein theactuating lever is engaged with said blister strip drive wheel duringrotation of the actuating lever to rotate said blister strip drive wheeland drive said strip.
 21. An inhaler according to claim 20, wherein theblister strip drive member comprises a plurality of spokes extendingfrom a hub, the spokes being spaced from each other such that a spokelocates between blister cavities as a blister strip passes around theblister strip drive member to engage and drive a strip as the blisterstrip drive member rotates, the blister strip drive member beingpositioned relative to a wall such that the distance between the hub andsaid wall is less than the height of a blister cavity such that onwardrotation of the wheel causes a blister cavity to be at least partiallysquashed or sandwiched between the hub and said wall.
 22. An inhalercomprising a housing to receive a strip having a plurality of blisters,each blister having a puncturable lid and containing a dose ofmedicament for inhalation by a user, a mouthpiece mounted to the housingand through which a dose of medicament is inhaled by a user, a blisterpiercing member mounted for rotation about a first axis and an actuatingmechanism including an actuating lever mounted for rotation about asecond axis to sequentially move each blister into alignment with theblister piercing member, wherein the actuating lever cooperates with theblister piercing member so that the blister piercing member pivots aboutsaid first axis in response to rotation of the actuating member from aninitial position about the second axis to puncture the lid of an alignedblister so an airflow through the blister is generated to entrain thedose contained therein and carry it, via the mouthpiece, into the user'sairway when a user inhales through the mouthpiece; wherein a wall isslideably mounted in the housing to divide it into unused and usedblister compartments, the wall comprising a baffle extending betweenopposing walls within the housing and an elongate foot extendingsubstantially at right-angles to the baffle and being slideably receivedwithin a recess in a wall of the housing.
 23. An inhaler according toclaim 22, wherein the baffle is attached to a central region of thefoot.
 24. An inhaler according to claim 23, wherein the foot is widestat its ends remote from the baffle such that only the ends of said footcontact the walls of said recess in the housing.